JP4615539B2 - Crystal manufacturing apparatus and crystal manufacturing method - Google Patents

Description

  The present invention relates to a crystal growth apparatus, a crystal production apparatus, and a crystal production method, and more particularly to a crystal growth apparatus, a crystal production apparatus, and a crystal production method for growing a high-quality GaN-based semiconductor crystal film with an inexpensive and simple configuration. It is.

  Conventionally, crystal growth of GaN, AlN, InN, and mixed crystals of these (hereinafter referred to as GaN-based) semiconductors is generally performed using MO-VPE (metal organic chemical vapor deposition). In order to perform crystal growth of a good quality GaN-based semiconductor by the -VPE method, it is necessary to perform the crystal growth temperature at a high temperature of 800 ° C. to 1200 ° C.

  However, when the crystal growth temperature is performed at the above-described high temperature by the MO-VPE method, the influence of thermal convection is large, and various devices are required.

  That is, in the MO-VPE method, conventionally, as shown in FIG. 10, the susceptor 3 is disposed at the tip of the shaft 2 inserted into the reaction vessel 1, and the substrate 4 is mounted on the upper surface of the susceptor 3. Placed. A gas injection pipe 5 that is opened at a close interval of several millimeters is disposed on the upper surface of the substrate 4, and the reaction gas is injected from the gas injection pipe 5 toward the substrate 4 from a substantially vertical direction. The substrate 4 on the susceptor 3 is heated to a predetermined high temperature by a heater 6 disposed below the susceptor 3. In the MO-VPE method, generally, the reaction gas (source gas) for crystal growth of the GaN-based semiconductor film is a group III source material such as TMG (trimethyl gallium), TMA (trimethyl aluminum), TMI ( Crystals that use organic metals such as trimethylindium), generally use ammonium as a group V source, and heat these source gases by induction heating or a resistance heating method as shown in FIG. The crystal is grown by being transported to the surface of the growth substrate 4.

  At this time, in the MO-VPE method, since the temperature of the substrate 4 is high, the ammonia as the group V raw material cannot effectively reach the substrate 4 due to the influence of thermal convection, and the nitrogen vacancy There is a problem that a GaN-based semiconductor film having poor crystallinity is grown.

  Therefore, conventionally, a semiconductor crystal film growth method, a semiconductor crystal layer growth apparatus, and the like described in Japanese Patent No. 2628404 and Japanese Patent No. 2562211 have been proposed.

  In the method for growing a semiconductor crystal film of Japanese Patent No. 2628404, a gas is supplied to the surface of a heated substrate from a direction parallel or inclined with respect to the substrate and a direction substantially perpendicular to the substrate. In the method of growing a semiconductor crystal film on the surface of a substrate, a reaction gas is supplied in a direction parallel or inclined to the surface of the substrate, and a reaction gas is contained in a direction substantially perpendicular to the surface of the substrate. The semiconductor crystal is supplied with a non-inert gas pressing gas, and the direction of the pressing gas, which is an inert gas, is changed to a direction in which a reactive gas supplied in a direction parallel to or inclined to the surface of the substrate is blown onto the substrate surface. Growing film.

  Specifically, as shown in FIG. 11, the substrate 13 is placed on the upper surface of the susceptor 12 housed in the reaction vessel 11, and the substrate 13 is heated to a set temperature by the heater 14 via the susceptor 12. A reaction gas is supplied through the reaction gas injection pipe 15 from a direction parallel to or inclined with respect to the substrate 13, and hydrogen or nitrogen containing no reaction gas is supplied through the sub injection pipe 16 from a direction substantially perpendicular to the substrate 13. A single family or mixed gas is supplied as a pressure gas. In FIG. 11, the susceptor 12 is attached to a shaft 17 that is rotationally driven, and the gas in the reaction vessel 11 is discharged from the exhaust port 18 by a vacuum pump. In FIG. 11, the temperature of the substrate 13 is measured by a radiation thermometer, and heating by the heater 14 is controlled.

  Therefore, by flowing gas from two directions with respect to the substrate 13, the problem of thermal convection is avoided, the reaction gas is efficiently transported to the surface of the substrate 13, and good crystalline GaN with few nitrogen vacancies. Crystal growth of a semiconductor film is attempted. Further, the substrate 13 is rotated at a rotational speed of several rpm to make the GaN-based semiconductor crystal growth region in the substrate 13 uniform.

  Further, in the semiconductor crystal layer growth apparatus disclosed in Japanese Patent No. 2556211, a reaction vessel, a susceptor disposed inside the reaction vessel for mounting the substrate, a means for heating the susceptor, and a reaction gas toward the substrate. A semiconductor crystal layer growth apparatus comprising a reaction gas supply pipe for supplying a transparent tube for introducing a gas into a reaction vessel, the transparent pipe having a cylindrical shape with a rear end narrower than a tip, and at least partly Is exposed to the outside of the reaction vessel, the tip of the transparent tube is opened in the reaction vessel, and the rear end of the transparent tube is connected to a gas supply source. A semiconductor crystal layer growth apparatus is proposed which is configured so that the state of the crystal layer can be observed.

  Specifically, it is an apparatus similar to the apparatus shown in FIG. 11 and has a cylindrical shape in which the tip (end close to the substrate) for supplying the pressurized gas is thicker than the rear end. It is said.

  Thereby, the return of the source gas is eliminated, the pipe for supplying the pressing gas is prevented from becoming dirty, and the source gas effectively reaches the substrate.

Furthermore, conventionally, a method for forming a semiconductor thin film has been proposed in which the thermal convection and the uniformity of the distribution of the GaN-based semiconductor crystal layer in the substrate are improved (see JP-A-8-56015). Specifically, the semiconductor thin film is formed by growing a GaN-based semiconductor crystal by supplying a source gas to the substrate from above the heated substrate. At this time, the substrate and the substrate heating source are used. By rotating at a high speed of 300 rpm or more, the source gas supplied from above the substrate is appropriately supplied to the vicinity of the substrate surface.
Japanese Patent No. 2628404 Japanese Patent No. 2556211 JP-A-8-56015

  However, in such a conventional crystal growth apparatus, the problem of the thermal convection has not been sufficiently improved, and it is necessary to improve the crystal growth with higher accuracy. However, there is a problem that the cost becomes high.

  That is, as shown in FIG. 10, a general MO-VPE apparatus has many gas injection pipes that are gas outlets in one direction. In the crystal growth apparatuses and methods described in the above patent publications, The gas blowing ports need to be supplied from two directions and from substantially orthogonal directions, and the crystal growth apparatus becomes complicated and expensive.

  Further, as in the crystal growth apparatus and method described in the above publication, when a gas is supplied from two directions, a film is grown only on a part of the substrate when the substrate is stationary. In order to grow the film, a mechanism for rotating the substrate is necessary, and there is a problem that the crystal growth apparatus is further complicated and expensive.

  Furthermore, the reaction vessel of the MO-VPE apparatus is generally made of quartz because it can be induction-heated or resistance-heated, can withstand use at high temperatures, and is relatively inexpensive to shape the reaction vessel. A manufactured tube is used as a reaction vessel. However, if a gas supply tube is formed in a substantially orthogonal direction using a quartz tube as a reaction vessel, shape processing of the reaction vessel becomes complicated and expensive. Furthermore, reaction products usually adhere to the inner wall of the reaction vessel, and when the amount of adhesion increases, the attached reaction products peel off and adhere to the crystal growth substrate, reducing the yield of the produced semiconductor crystals. Problem occurs. In order to solve this problem, when a certain amount of reaction product adheres to the inner wall of the reaction vessel, the reaction vessel is washed to remove the reaction product adhering to the inner wall of the reaction vessel. As described above, when the gas is supplied in approximately two directions so as to have a complicated shape, there is a problem that it is difficult to perform the washing operation of the reaction vessel and the operability when washing the reaction vessel is poor.

  In addition, the reaction vessel may be formed using stainless steel in addition to the quartz. However, when crystal growth of a GaN-based semiconductor film is performed, it is necessary to cope with a high temperature of 1000 ° C. or higher. In order to cope with high temperatures, various devices are required for the cooling mechanism of the reaction vessel. In this case, if the reaction vessel is formed in a complicated shape to supply gas from approximately two directions as in the conventional case, it is difficult to provide a cooling mechanism in the reaction vessel, and the structure becomes even more complicated. Thus, there is a problem that the crystal growth apparatus becomes more expensive.

  Further, in a general MO-VPE apparatus, in order to grow a GaN-based semiconductor film at a high temperature, as shown in FIG. The problem of thermal convection is dealt with by blowing the source gas to the substrate at a high speed of sec. However, if the source gas outlet is arranged near the substrate, the source gas is less spread and the area is increased. There is a problem that a uniform film cannot be grown.

  Further, in the method for growing a semiconductor crystal film disclosed in Japanese Patent No. 2628404 and Japanese Patent No. 2562211, the reaction product adheres to the blowout port due to the temperature rise of the gas blowout port and the source gas before reaching the substrate surface. The reaction cannot be prevented, and improvement is necessary for more accurate crystal growth. That is, in the above conventional method, it is necessary to dispose the source gas blowout port supplied from a direction parallel or inclined with respect to the substrate as close as several mm to the substrate or the susceptor holding the substrate. The temperature of the outlet rises. As a result, it is impossible to prevent a reaction product from adhering to the outlet or reacting before the source gas reaches the substrate surface, and the crystal growth accuracy deteriorates.

  Furthermore, in the method for forming a semiconductor thin film described in JP-A-8-56015, the source gas outlet is disposed in the vicinity of the substrate, and the temperature of the outlet rises due to thermal convection. In addition, it is impossible to prevent the reaction product from adhering to the outlet or reacting before the source gas reaches the substrate surface, and the crystal growth accuracy deteriorates. In addition, it is necessary to rotate the substrate and the heating source at a high speed, and special measures are required for the seal portion between the rotating shaft that rotates the substrate and the heating source at a high speed and the reaction vessel. There is a problem that it is necessary to consider the mechanical strength accompanying the maintenance, the structure becomes more complicated, and the crystal growth apparatus becomes more expensive.

  Therefore, the present invention prevents the raw gas from reaching the crystal growth surface of the substrate by thermal convection due to heating of the substrate and prevents an inexpensive apparatus capable of performing good crystal growth with a simple configuration and It aims to provide a method.

  In addition, the present invention appropriately supplies the source gas to the crystal growth surface of the substrate, performs better crystal growth with a simple configuration, suppresses the adhesion of the reaction product to the inner wall of the reaction vessel, An object of the present invention is to provide an apparatus and a method having good usability by reducing the frequency of washing the reaction vessel.

Manufacturing apparatus of the present invention, the substrate held by the susceptor at a predetermined reaction vessel was injected into the substrate heating situ Tsuhara material gas to a predetermined temperature, the crystal manufacturing apparatus for growing a crystal by vapor phase reaction a first gas supply pipe for injecting the raw material gas, a second gas supply pipe for injecting a second gas which does not contribute directly to the reaction, a third gas which does not contribute directly to the reaction in the reaction vessel A gas introduction pipe to be introduced, and the surface of the substrate on which crystal growth is performed is installed in a state facing a direction opposite to a vector opposite to gravity, and the first gas supply pipe has the surface The source gas blowout port is disposed in a state of facing substantially perpendicular to the surface of the substrate on which crystal growth is performed, and the second gas supply pipe faces the surface of the substrate on which crystal growth is performed In the state of facing and Is disposed in a state of injecting the second gas toward the outer position than the outer periphery of the plate, the gas inlet pipe is radially outer of the first gas supply pipe about said first gas supply pipe And the gas blowout port extends to the substrate side from the blowout port of the first gas supply pipe from the direction facing the surface of the substrate on which crystal growth is performed. Then, the substrate is arranged so as to extend to a radially outer position at substantially the same position as the surface on the crystal growth side of the substrate.

According to the above configuration, the second gas injected from the second gas supply pipe suppresses the spread of the source gas injected from the first gas supply pipe to the substrate, and the source gas is further grown on the crystal growth surface of the substrate. In addition to being able to supply properly to the reactor, it is possible to perform better crystal growth with a simple configuration, and to reduce the frequency of cleaning the reaction vessel by suppressing the adhesion of reaction products to the inner wall of the reaction vessel Can improve usability.

In addition, the third gas injected from the gas introduction pipe further suppresses the spread of the source gas injected from the first gas supply pipe to the substrate, and further supplies the source gas more appropriately to the crystal growth surface of the substrate. In addition to being able to perform better crystal growth with less material gas with a simple structure, the adhesion of reaction products to the inner wall of the reaction vessel is further suppressed, and the frequency of cleaning the reaction vessel is reduced. Can be reduced and usability can be improved.

Crystal production method of the present invention, the crystal production to grow a predetermined a substrate held on a susceptor in a reaction vessel by injecting heated situ Tsuhara material gas to a predetermined temperature to the substrate, the crystal by vapor phase reaction in the method, a first gas supply pipe for injecting the raw material gas, a second gas supply pipe for injecting a second gas which does not directly contribute to the reaction, the third gas the reaction vessel which does not contribute directly to the reaction A gas introduction pipe for introducing into the substrate, and the surface of the substrate on which crystal growth is to be performed faces in a direction opposite to the vector in the direction opposite to gravity, and crystal growth of the substrate is performed. The raw material gas is blown out from the raw material gas blowing port of the first gas supply pipe disposed in a state of being substantially perpendicularly opposed to the surface on the performing side to the surface on the crystal growth side of the substrate, and The side of the substrate where the crystal is grown A second gas that does not directly contribute to the reaction is injected from the second gas supply pipe toward a position outside the outer periphery of the substrate from a direction substantially facing the surface, with the first gas supply pipe as the center. From the direction in which the gas blowing port is disposed at the radially outer position of the first gas supply pipe and the gas blowing port faces the surface on the crystal growth side of the substrate, from the blowing port of the first gas supply pipe also extends to the substrate side, in the reaction from extending to a position substantially radially outward of the same position as the side surface of crystal growth of the substrate is disposed said gas inlet tube The crystal growth is performed by introducing a third gas that does not directly contribute.

  According to the above configuration, it is possible to prevent the source gas from reaching the crystal growth surface of the substrate from being inhibited by thermal convection due to heating of the substrate, and good crystal growth can be easily performed at low cost.

  In addition, the second gas injected from the second gas supply pipe suppresses the spread of the raw material gas injected from the gas supply pipe to the substrate, thereby further appropriately supplying the raw material gas to the crystal growth surface of the substrate. It is possible to perform better crystal growth with a simple structure, and to reduce the frequency of washing of the reaction vessel by suppressing the adhesion of reaction products to the inner wall of the reaction vessel. Can be improved.

In addition, the third gas injected from the gas introduction pipe further suppresses the spread of the source gas injected from the first gas supply pipe to the substrate, and further supplies the source gas more appropriately to the crystal growth surface of the substrate. In addition to being able to perform better crystal growth with less material gas with a simple structure, the adhesion of reaction products to the inner wall of the reaction vessel is further suppressed, and the frequency of cleaning the reaction vessel is reduced. Can be reduced and usability can be improved.

  In this case, for example, the crystal growth method may perform at least one step in which the heating temperature of the substrate becomes 700 ° C. or higher.

  According to the above configuration, it is possible to prevent the arrival of the source gas to the crystal growth surface of the substrate even in a process of 700 ° C. or higher where the thermal convection becomes remarkable, and a good crystal can be easily and inexpensively. Can do growth.

  Further, for example, in the crystal growth method, a portion of the substrate other than the surface on the crystal growth side is covered with a predetermined cover that scatters, absorbs, and reflects radiant heat from the susceptor as the heating source. Then, the substrate may be heated to perform the crystal growth.

  According to the above configuration, the temperature rise around the outer periphery of the susceptor can be reduced by radiant heat from the susceptor that is a heating source, and it is even more appropriate that the arrival of the source gas to the crystal growth surface of the substrate is inhibited. In addition to preventing GaN-based films from adhering to the outer surface of the susceptor and preventing the quality of crystals grown on the substrate from deteriorating, simpler and cheaper to achieve better crystal growth Can do.

  Further, for example, in the crystal growth method, the outer surface of the cover may be formed of quartz having a non-mirror finish.

  According to the above configuration, it is possible to further suppress an increase in the temperature around the outer periphery of the susceptor due to radiant heat from the susceptor that is a heating source, and the arrival of the source gas to the crystal growth surface of the substrate is inhibited. Can be prevented more appropriately, and the GaN-based film adhering to the outer surface of the susceptor can be prevented from peeling off, and better crystal growth can be performed easily and inexpensively.

Further, for example, in the crystal growth method, the source gas blow-out port of the first gas supply pipe and the surface of the substrate on the side where the crystal growth is performed are arranged at a predetermined distance shorter than 300 mm. May be.

According to the above configuration, it is possible that the first gas supply pipe can be reduced deposition of GaN-based reaction product of the first gas supply pipe is heated, reducing the frequency of replacement of the first gas supply pipe At the same time, it is possible to improve the crystallinity by reducing the influence of the GaN-based reaction product adhering to the first gas supply pipe on the crystal generated on the substrate, and to grow the GaN-based film. depending on the thickness and characteristics, the distance between the outlet and the crystal growth surface of the substrate of the first gas supply pipe appropriately set, it is possible to improve the freedom of layout.

According to the crystal manufacturing apparatus of the present invention, the second gas supply pipe that injects the second gas that does not directly contribute to the reaction is in a state facing the surface on the side on which the crystal growth of the substrate is performed, and Since the second gas is disposed in a state of being ejected toward a position outside the outer periphery of the substrate, the second gas ejected from the second gas supply tube causes the first gas supply tube to travel to the substrate. While suppressing the spread of the injected source gas, the source gas can be appropriately supplied to the crystal growth surface of the substrate, and even better crystal growth can be performed with a simple configuration. The reaction product can be prevented from adhering to the inner wall, the frequency of washing the reaction vessel can be reduced, and the usability can be improved.

Furthermore, a gas inlet tube for introducing a third gas which does not contribute directly to the reaction in the reaction vessel, as well as a location disposed radially outward of the first gas supply pipe around the first gas supply pipe, The gas blowing port extends from the direction facing the surface of the substrate on which crystal growth is performed to the substrate side rather than the blowing port of the first gas supply pipe, and is an abbreviation of the surface of the substrate on which crystal growth is performed. Since it is arranged to extend to the radially outer position at the same position, the spread of the source gas injected from the first gas supply pipe to the substrate by the third gas injected from the gas introduction pipe In addition, the source gas can be appropriately supplied to the crystal growth surface of the substrate, and the crystal can be further improved with a simple configuration and with less source gas. Of reaction products on the inner wall Won, the cleaning frequency of the reaction vessel can be reduced, thereby improving the usability.

  According to the crystal manufacturing method of the present invention, it is possible to prevent the arrival of the source gas to the crystal growth surface of the substrate due to thermal convection by heating the substrate, and to perform good crystal growth easily and inexpensively. be able to.

Further, the second gas supply pipe for injecting the second gas that does not directly contribute to the reaction is oriented in a direction facing the surface on the side of crystal growth of the substrate and outside the outer periphery of the substrate. Since the second gas is injected toward the position, the second gas injected from the second gas supply pipe spreads the source gas injected from the first gas supply pipe onto the substrate. In addition, it is possible to appropriately supply the source gas to the crystal growth surface of the substrate, and to achieve better crystal growth with a simple configuration, and the reaction product on the inner wall of the reaction vessel Adhesion can be suppressed, the frequency of washing the reaction container can be reduced, and usability can be improved.

Furthermore, a gas inlet tube for introducing a third gas which does not contribute directly to the reaction in the reaction vessel, as well as a location disposed radially outward of the first gas supply pipe around the first gas supply pipe, The gas blowing port extends from the direction facing the surface of the substrate on which crystal growth is performed to the substrate side rather than the blowing port of the first gas supply pipe, and is an abbreviation of the surface of the substrate on which crystal growth is performed. Since it is arranged to extend to the radially outer position at the same position, the spread of the source gas injected from the first gas supply pipe to the substrate by the third gas injected from the gas introduction pipe In addition, the source gas can be appropriately supplied to the crystal growth surface of the substrate, and the crystal can be further improved with a simple configuration and with less source gas. Of reaction products on the inner wall Won, the cleaning frequency of the reaction vessel can be reduced, thereby improving the usability.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. The embodiments described below are preferred embodiments of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. As long as there is no description which limits, it is not restricted to these aspects.

  FIG. 1 is a diagram showing a first embodiment of the crystal growth apparatus and crystal growth method of the present invention, and FIG. 1 applies the first embodiment of the crystal growth apparatus and crystal growth method of the present invention. It is the front schematic block diagram seen from the surface substantially parallel with respect to the flow of the reaction gas of the crystal growth apparatus.

In this embodiment, the substrate is disposed with the crystal growth surface facing downward, and the source gas is supplied from the gas supply pipe disposed below the crystal growth surface of the substrate to the crystal growth surface of the substrate. The GaN-based semiconductor crystal film is grown by spraying toward the surface .

  In FIG. 1, a crystal growth apparatus 20 is provided with a substantially cylindrical reaction vessel 21. The reaction vessel 21 is closed at its upper end by an upper flange or the like (not shown), and at its lower end by a lower flange (not shown). Is formed in a sealed space that is blocked by the external air atmosphere.

  A susceptor rod 22 that passes through the upper flange while being in close contact with the upper flange and is movable by a predetermined amount in FIG. 1 is inserted into the reaction vessel 21. A susceptor 24 serving as a heating source is attached via a susceptor cover 23 made of quartz. On the upper side of the susceptor cover 23, a communication pipe 25 having a hole through which the susceptor rod 22 passes is disposed.

  The susceptor 24 is formed in a columnar shape whose upper and lower surfaces are planar in FIG. 1, for example, a columnar shape, is formed of carbon, and its surface is coated with SiC (silicon carbide). In FIG. 1, a crystal growth substrate 26 is attached to the lower surface of the susceptor 24, and the substrate 26 has a substantially cylindrical shape disposed so as to cover a part of the outer peripheral surface and the lower surface of the susceptor 24, for example, The susceptor 24 is brought into close contact with the lower surface of the susceptor 24 by the cylindrical susceptor holder 27 and the crystal growth surface (surface on which crystal growth is performed) is directed downward, and the susceptor 24 is self-weighted. The susceptor holder 27 is attached to the lower surface of the susceptor 24 while being sandwiched between the lower holding portion 27a. That is, when the reaction vessel 21 of the crystal growth apparatus 20 is arranged in the vertical direction, the substrate 26 is arranged in a state where the crystal growth surface faces a vector in the direction opposite to the vertical downward direction that is the gravity direction. It is installed.

  The substrate 26 is placed at an arbitrary position in the reaction vessel 21 by moving the susceptor rod 22 in the vertical direction.

  The crystal growth apparatus 20 is provided with a gas supply pipe 28 that penetrates a lower flange that closes the lower end of the reaction vessel 21 and enters a predetermined amount into the reaction vessel 21. The injection port is disposed in a state in which it is directed in a direction substantially perpendicular to the crystal growth surface of the substrate 26. That is, the gas supply pipe 28 is located in a state where its injection port is located almost directly below the center of the crystal growth surface of the substrate 26 and faces the crystal growth surface of the substrate 26 substantially vertically, and faces upward. It is arranged by.

  In the crystal growth apparatus 20, an induction heating coil 29 is disposed outside the reaction vessel 21 so as to cover the outside of the susceptor 24, and the induction heating coil 29 is supplied with a high-frequency current from a power source (not shown). As a result, an eddy current is generated inside the susceptor 24 serving as a heating source of the substrate 26, and the substrate 26 attached to the lower surface of the susceptor 24 is heated to a predetermined high temperature.

  From the gas supply pipe 28, TMG, TMA, TMI, ammonia, hydrogen, and nitrogen, which are raw material gases for crystal growth on the substrate 26, are supplied. Depending on the source gas, GaN, AlN, InN or a mixed crystal thereof grows.

  Next, the operation of the present embodiment will be described. The crystal growth apparatus 20 places the substrate 26 on the holding part 27 a of the susceptor holder 27 and inserts the susceptor 24 into the susceptor holder 27, whereby the holding part 27 a of the susceptor holder 27 and the susceptor 24 are placed by the weight of the susceptor 24. In the meantime, the substrate 26 is sandwiched with the crystal growth surface facing downward.

  The susceptor cover 24 and the connecting pipe 26 connected to the susceptor rod 22 are attached to the susceptor holder 27 that holds the substrate 25 and accommodates the susceptor 24, and the upper flange that penetrates the susceptor rod 22 is attached to the upper end of the reaction vessel 21. Attach and close the upper end of the reaction vessel 21.

  Further, a lower flange to which the gas supply pipe 28 is attached is attached to the lower end of the reaction vessel 21 to close the lower end of the reaction vessel 21.

  Next, the susceptor rod 22 is moved up and down to adjust the position of the gas supply pipe 28 and the substrate 26, and then the air in the reaction vessel 21 is exhausted, and the reaction vessel 21 is directly subjected to the crystal growth reaction. Replace with non-contributing nitrogen and hydrogen gas.

  Therefore, the substrate 26 is disposed in a state where the crystal growth surface faces the vector in the direction opposite to the gravity, and the gas supply pipe 28 has an injection port at the center of the crystal growth surface of the substrate 26. It is positioned directly below, facing substantially perpendicular to the crystal growth surface of the substrate 26, and facing upward.

  Thereafter, the crystal growth apparatus 20 energizes the induction heating coil 29 to generate an eddy current in the susceptor 24 to heat the substrate 26 to a predetermined high temperature.

  In this state, when the source gases TMG, TMA, TMI, ammonia, hydrogen, and nitrogen are supplied from the gas supply pipe 28 in this state, the crystal growth apparatus 20 forms GaN, AlN, InN or these on the crystal growth surface of the substrate 26. The mixed crystal grows.

  At this time, the temperature of the raw material gas injected from the injection port of the gas supply pipe 28 is lower than the temperature in the vicinity of the substrate 26, the susceptor 24, or the susceptor holder 27, and is thus injected from the gas supply pipe 28 toward the substrate 26. The raw material gas is heated on the surface of the substrate 26 to generate thermal convection, but the substrate 26 is disposed with its crystal growth surface facing downward, and the gas supply pipe 28 is disposed below the substrate 26 from the crystal growth surface. Therefore, the thermal convection of the source gas flows outward from the center of the substrate 26 in the radial direction.

  Therefore, fresh raw material gas injected from the gas supply pipe 28 toward the crystal growth surface of the substrate 26 is always supplied to the surface of the substrate 26, and the crystal growth apparatus 20 has a complicated and expensive structure as in the conventional case. Therefore, a high-quality GaN-based semiconductor crystal film can be grown on the surface of the substrate 26 with a simple structure and an inexpensive crystal growth apparatus 20.

  In addition, the distance between the injection port of the gas supply pipe 28 and the substrate 26 can be made wider than before, and a high quality GaN, AlN, InN or mixed crystal semiconductor crystal film thereof can be formed over a wide range on the surface of the substrate 26. Can grow.

  In the present embodiment, TMG, TMA, TMI, ammonia, hydrogen, and nitrogen are used as source gases. However, any source gas that can grow a GaN-based crystal can be used. The same applies to.

  In addition, the material of the components in the reaction vessel 21 of the crystal growth apparatus 20 is not limited to the above as long as it fulfills the function described above.

  FIG. 2 is a diagram showing a second embodiment of the crystal growth apparatus and the crystal growth method of the present invention, and FIG. 2 applies the second embodiment of the crystal growth apparatus and the crystal growth method of the present invention. It is a figure which shows the crystal growth process by the manufactured crystal growth apparatus.

In the present embodiment, at least one step of heating the substrate to 700 ° C. or higher is performed in the crystal growth step .

  In the present embodiment, crystal growth is performed using the crystal growth apparatus 20 used in the first embodiment, and in the description of the present embodiment, the first embodiment is used. The following description will be made using the used symbols as they are.

  When crystal growth of a GaN film is performed using the crystal growth apparatus 20 shown in FIG. 1, a crystal growth process with a temperature sequence as shown in FIG. 2 is performed. FIG. 2 shows the temperature in each processing step as time passes, with the horizontal axis as the time axis and the vertical axis as the temperature.

  When the substrate 26 held by the susceptor 24 is positioned and set in the reaction vessel 21, the crystal growth apparatus 20 first raises the temperature of the substrate 26 from room temperature to 1100 ° C. in a hydrogen atmosphere. After the process S1, a high temperature heat treatment step S2 is performed in which the substrate 26 is heat treated at 1100 ° C. in a hydrogen atmosphere for cleaning.

  Next, the crystal growth apparatus 20 performs a temperature lowering process S3 for lowering the substrate 26 heated to 1100 ° C. to 500 ° C., and performs a low temperature buffer layer growing process S4 to grow a GaN layer at a low temperature.

  Next, the crystal growth apparatus 20 performs a temperature raising process S5 for raising the temperature of the substrate 26 to 1050 ° C., performs a growth process S6 for growing a high-temperature GaN film at 1050 ° C., and finally performs a temperature lowering process. S7 is performed to cool the substrate 26 to room temperature.

  As described above, when at least one process step of 700 ° C. or higher is provided in the crystal growth process, the crystal growth apparatus 20 has a simple configuration without a complicated and expensive configuration, as in the past, and A cheaper crystal growth apparatus 20 can grow a higher quality GaN-based semiconductor crystal film on the surface of the substrate 26.

  When crystal growth is performed by performing each of the above process steps, in each step process at a temperature of 700 ° C. or higher, thermal convection on the crystal growth surface of the substrate 26 occurs more markedly than in the case of 700 ° C. or lower, By appropriately setting the positional relationship between the crystal growth surface of the substrate 26 and the injection port of the gas supply pipe 28, fresh raw material gas is stably supplied to the crystal growth surface of the substrate 26 even at a high temperature of 700 ° C. or higher. can do.

  In addition to the above growth process, when GaN-based crystal growth is performed, the process can be similarly applied to a process that undergoes a high-temperature process of 700 ° C. or higher.

  In the present embodiment, the growth process S6 for growing the high-temperature GaN film is performed at a high temperature of 700 ° C. or more. However, the function can be satisfied even if it is other than the GaN film. Any material can be applied as appropriate.

  FIG. 3 is a diagram showing a third embodiment of the crystal growth apparatus and crystal growth method of the present invention, and FIG. 3 applies the third embodiment of the crystal growth apparatus and crystal growth method of the present invention. It is the front schematic block diagram seen from the surface substantially parallel with respect to the flow of the reaction gas of the crystal growth apparatus.

In the present embodiment, a cover other than the crystal growth surface of the substrate is covered with a cover that scatters, absorbs, and reflects radiant heat from the heating source of the substrate .

  The present embodiment is applied to a crystal growth apparatus similar to the crystal growth apparatus 20 used in the first embodiment. In the description of the present embodiment, the first embodiment is applied. The same components as those of the crystal growth apparatus 20 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 3, the crystal growth apparatus 30 holds the substrate 26 in a state where the substrate 26 is sandwiched with the crystal growth surface facing downward by the carbon susceptor 24 whose surface is coated with SiC and the holding portion 31a of the susceptor holder 31. The susceptor holder 31 is formed of opaque quartz. Further, a susceptor cover 32 made of opaque quartz is disposed on the susceptor 24, and the lower end portion of the susceptor rod 22 is attached to the susceptor cover 32.

  That is, the substrate 26 has a surface opposite to the crystal growth surface in close contact with the susceptor 24 as a heating source, and a surface other than the crystal growth surface is formed of opaque quartz together with the susceptor 24 as a heating source. The opaque quartz is covered with the susceptor holder 31 and the susceptor cover 32 as covers. The opaque quartz efficiently scatters, absorbs, and reflects radiant heat from the susceptor 24 as a heating source.

  When crystal growth is performed using the crystal growth apparatus 20 of the present embodiment, a high-frequency current is passed through the induction heating coil 29 to generate an eddy current inside the susceptor 24 that serves as a heating source for the substrate 26, thereby generating a susceptor 24. The substrate 26 attached to the lower surface of the substrate 26 is heated to a predetermined high temperature, and a source gas is injected from the gas supply pipe 28 disposed below the crystal growth surface of the substrate 26 toward the crystal growth surface of the substrate 26. . The injected source gas is heated at the crystal growth surface of the substrate 26 and the temperature rises. However, since the upper part of the source gas is blocked by the substrate 26, the crystal growth occurs in the radial direction of the substrate 26 from the center of the substrate 26. It flows along the surface, and fresh raw material gas is always supplied to the crystal growth surface of the substrate 26.

  In particular, the substrate 6 and the susceptor 24 that is a heating source are covered with a susceptor holder 31 and a susceptor cover 32 that are made of opaque quartz, and radiant heat from the susceptor 24 that is a heating source is applied to the susceptor holder 31 and the susceptor 24. Scattering, absorption, and reflection by the susceptor cover 32 can suppress an increase in temperature outside the susceptor holder 31 and the susceptor cover 32. Therefore, the thermal convection of the source gas injected from the gas supply pipe 28 onto the crystal growth surface of the substrate 26 can be suppressed to be small, and the supply efficiency of the source gas to the crystal growth surface of the substrate 26 can be improved. As a result, a high-quality GaN-based semiconductor crystal film can be grown on the surface of the substrate 26 more efficiently.

  Further, when crystal growth is performed, a GaN-based film is attached to the outer surfaces of the susceptor holder 31 and the susceptor cover 32, but the susceptor holder 31 and the susceptor cover 32 are made of opaque quartz. The temperature rise of the susceptor holder 31 and the susceptor cover 32 itself can be suppressed, and the adhesion amount of this film can be suppressed.

  Therefore, the GaN-based film attached to the susceptor holder 31 and the susceptor cover 32 increases in amount and peels off and scatters onto the crystal growth surface of the substrate 26, thereby suppressing a decrease in crystal growth quality and a decrease in yield. At the same time, the frequency of cleaning in the crystal growth apparatus 30 (in the reaction vessel 21) to prevent such deterioration in crystal quality and yield can be reduced, and crystal growth can be achieved while improving crystal growth quality. The utilization efficiency of the device 30 can be improved.

  In the present embodiment, TMG, TMA, TMI, ammonia, hydrogen, and nitrogen are used as source gases. However, any source gas that can grow a GaN-based crystal can be used. The same applies to.

  Further, the material of the components in the reaction vessel 21 of the crystal growth apparatus 30 is not limited to the above as long as it fulfills the function described above.

  FIG. 4 is a diagram showing a fourth embodiment of the crystal growth apparatus and crystal growth method of the present invention, and FIG. 4 applies the fourth embodiment of the crystal growth apparatus and crystal growth method of the present invention. It is a front view of the susceptor holder of the crystal growth apparatus.

In the present embodiment, the outer surface of the susceptor holder is a non-mirror surface .

  In FIG. 4, the susceptor holder 40 is formed in a substantially cylindrical shape from quartz, and is annealed at a high temperature to reduce thermal distortion after the formation of the processing. Since the normally annealed quartz surface is in a mirror state, the susceptor holder 40 performs a cutting process on the outer surface after the annealing, thereby forming a large number of minute irregularities to form the outer surface. Non-specular state.

Using this susceptor holder 40 having a non-specular outer surface, the crystal growth apparatus 20 shown in FIG. 1 is used to grow a crystal in the same manner as in the first or second embodiment. As the crystal grows, the film 41 of the GaN-based material adheres to the outer surface of the susceptor holder 40. However, the peeling of the film 41 attached to the outer surface of the susceptor holder 40 is suppressed, and the crystal growth quality is improved. The utilization efficiency of the growth apparatus can be improved.

  That is, conventionally, as shown in FIG. 5, when the susceptor holder 42 is formed of quartz, since the one annealed at a high temperature is used as it is, the outer surface thereof is in a mirror state as described above. ing. When crystal growth is performed on the substrate using the susceptor holder 42 in the mirror state, the film 43 adheres to the outer surface of the susceptor holder 42 along with the crystal growth, and the film of the film 43 increases as the number of times of crystal growth increases. As the thickness increases, film peeling occurs in which a portion 43a of the film 43 attached to the outer surface of the susceptor holder 42 is peeled off due to the fluctuation of the temperature of the susceptor holder 42 that occurs in the crystal growth process. The peeled film 43a may be lifted by the source gas supplied into the reaction vessel or the thermal convection of the source gas, and may adhere to the crystal growth surface of the substrate. When the film 43a thus peeled adheres to the crystal growth surface of the substrate, defects in the crystal film formed on the substrate increase, and the yield of the crystal growth substrate decreases. Therefore, in the conventional crystal growth apparatus, when the film 43 adheres to the susceptor holder 42 to such an extent that film peeling occurs, the susceptor holder 42 is washed to remove the film 43 from the outer surface of the susceptor holder 42. .

  However, as described above, the susceptor holder 40 according to the present embodiment is in a non-specular state with irregularities formed on its outer surface by cutting or the like. Therefore, the film 41 adhering to the outer surface of the susceptor holder 40 during crystal growth adheres to the susceptor holder 40 with a stronger adhesion force, and is prevented from peeling off from the outer surface of the susceptor holder 40 during crystal growth. be able to.

  According to the applicant's experiment, when the crystal growth was performed using a susceptor holder 40 made of quartz whose outer surface was cut to a non-mirror surface, cracks occurred even when used at a high temperature of about 1200 ° C. The number of times that the crystal can be grown without washing with one susceptor holder 40 as compared to the case of using the conventional susceptor holder 42 whose outer surface is a mirror surface does not occur. Increased significantly.

  As a result, the crystal growth quality and the utilization efficiency of the crystal growth apparatus can be further improved.

  In the present embodiment, transparent quartz is used as the susceptor holder 40 and the outer surface thereof is in a non-mirror surface state. However, as described in the third embodiment, opaque quartz is used. Thus, a susceptor holder whose outer surface is in a non-mirror surface state may be used. In this case, the operational effects of the third embodiment can be further improved. That is, if the outer surface of the opaque quartz susceptor holder is in a non-specular state, the radiation from the susceptor can be further reduced by the unevenness of the outer surface, the temperature outside the susceptor holder can be further reduced, and high quality A GaN-based semiconductor crystal film can be grown more efficiently on the substrate surface.

  FIG. 6 is a diagram showing a fifth embodiment of the crystal growth apparatus and the crystal growth method of the present invention, and FIG. 6 applies the fifth embodiment of the crystal growth apparatus and the crystal growth method of the present invention. It is the front schematic block diagram seen from the surface substantially parallel with respect to the flow of the reaction gas of the crystal growth apparatus.

In the present embodiment, the distance between the crystal growth surface of the substrate and the injection port of the gas supply pipe is set to 300 mm or less .

  The present embodiment is applied to a crystal growth apparatus similar to the crystal growth apparatus 20 used in the first embodiment. In the description of the present embodiment, the first embodiment is applied. The same components as those of the crystal growth apparatus 20 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 6, the crystal growth apparatus 50 holds the substrate 26 with the crystal growth surface facing downward by the susceptor 24 and the holding portion 27 a of the susceptor holder 27, and the upper side of the susceptor 24 is below the susceptor rod 22. A susceptor cover 32 attached to the tip is disposed. On the upper side of the susceptor cover 23, a communication pipe 25 having a hole through which the susceptor rod 22 is formed is disposed. The susceptor rod 22 penetrates the upper flange while being in close contact with the upper flange (not shown) of the reaction vessel 21. In addition, a predetermined amount can be moved in the vertical direction of FIG.

  The crystal growth apparatus 50 is provided with a gas supply pipe 28 that passes through a lower flange that closes the lower end of the reaction vessel 21 and enters a predetermined amount into the reaction vessel 21. The injection port 28 a is disposed in a state of being substantially perpendicular to the crystal growth surface of the substrate 26. That is, the gas supply pipe 28 is in a state in which the injection port 28a is located directly below the center of the crystal growth surface of the substrate 26 and faces the crystal growth surface of the substrate 26 substantially vertically and faces upward. It is arranged by.

  And the board | substrate 26 moves the board | substrate 26 currently hold | maintained at the susceptor 24 and the susceptor holder 24 to an up-down direction by moving the susceptor rod 22 to an up-down direction, and position with the injection port 28a of the gas supply pipe | tube 28 In the crystal growth apparatus 50 of the present embodiment, the distance d between the crystal growth surface of the substrate 26 and the injection port 28 of the gas supply pipe 28 is set to 200 mm.

  When crystal growth is performed using the crystal growth apparatus 50, the substrate 26 is held by the susceptor 24 and the susceptor holder 27 with the crystal growth surface facing downward, and then the susceptor cover 23 to which the susceptor rod 22 is attached. Is inserted into the reaction vessel 21, and the susceptor rod 22 is moved in the vertical direction so that the distance d from the injection port 28a of the gas supply pipe 28 is set to 200 mm.

  Next, an eddy current is generated in the susceptor 24 by the induction heating coil 29 for the substrate 26 to heat the substrate 26 using the susceptor 24 as a heating source, and TMG, TMA, TMI, ammonia, which are source gases, are supplied from the gas supply pipe 28. Hydrogen and nitrogen are injected toward the substrate 26.

  Since the temperature of the gas injected from the gas supply pipe 28 is lower than the temperature in the vicinity of the substrate 26, the susceptor 24, or the susceptor holder 27, it is heated on the surface of the substrate 26 and heat convection is generated. However, the thermal convection of the source gas is performed in a state where the substrate 26 is disposed with its crystal growth surface facing downward, and the gas supply pipe 28 injects the source gas from below the substrate 26 toward the crystal growth surface. Since it is disposed, it flows outward in the radial direction from the center of the substrate 26, and a fresh raw material gas can always be supplied to the crystal growth surface of the substrate 26.

  In particular, although the distance d between the injection port 28a of the gas supply pipe 28 and the crystal growth surface of the substrate 26 is set to be significantly longer than the several millimeters of the prior art of 200 mm, as described above, the gas supply pipe The source gas injected from 28 to the substrate 26 can be appropriately supplied to the crystal growth surface of the substrate 26 without being affected by thermal convection.

  Therefore, a GaN-based semiconductor crystal film having a good crystallinity with a surface morphology of a mirror surface can be grown on the surface of the substrate 26 with a simple structure and an inexpensive crystal growth apparatus 50.

  Further, since the distance d between the injection port 28a of the gas supply pipe 28 and the crystal growth surface of the substrate 26 is increased to 200 mm, the temperature increase of the gas supply pipe 28 can be suppressed, which has been a problem in the past. Product adhesion to the gas supply pipe 28 can be prevented. As a result, the crystallinity of the GaN-based semiconductor crystal film generated on the substrate 26 can be further improved.

  In the present embodiment, TMG, TMA, TMI, ammonia, hydrogen, and nitrogen are used as source gases. However, any source gas that can grow a GaN-based crystal can be used. The same applies to.

  In addition, the material of the components in the reaction vessel 21 of the crystal growth apparatus 50 is not limited to the above as long as it fulfills the function described above.

  Furthermore, in the present embodiment, the distance d between the injection port 28a of the gas supply pipe 28 and the crystal growth surface of the substrate 26 is set to 200 mm, but is not limited to 200 mm, and if it is 300 mm or less, Good crystallinity can be obtained. It should be noted that the shorter the distance d between the injection port 28a of the gas supply pipe 28 and the crystal growth surface of the substrate 26, the higher the growth rate of the GaN-based crystal film, and the longer the distance d, the smaller the film thickness distribution. . Therefore, the distance d between the injection port 28a of the gas supply pipe 28 and the crystal growth surface of the substrate 26 can be appropriately set according to the use of the crystal film to be generated, and the crystal growth conditions in the crystal growth of the GaN-based material. In addition, the layout margin of the crystal growth apparatus 50 can be increased.

  FIG. 7 is a diagram showing a sixth embodiment of the crystal growth apparatus and the crystal growth method of the present invention, and FIG. 7 applies the sixth embodiment of the crystal growth apparatus and the crystal growth method of the present invention. It is the front schematic block diagram seen from the surface substantially parallel with respect to the flow of the reaction gas of the crystal growth apparatus.

In the present embodiment, a second gas supply pipe is provided for injecting a gas that does not directly contribute to the reaction toward the substrate in the circumferential direction of the substrate .

  The present embodiment is applied to a crystal growth apparatus similar to the crystal growth apparatus 20 used in the first embodiment. In the description of the present embodiment, the first embodiment is applied. The same components as those of the crystal growth apparatus 20 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 7, the crystal growth apparatus 60 holds the substrate 26 with the crystal growth surface facing downward by the holding part 27 a of the susceptor 24 and the susceptor holder 27. A susceptor cover 32 attached to the tip is disposed. On the upper side of the susceptor cover 23, a communication tube 25 having a hole through which the susceptor rod 22 is formed is disposed. In addition, a predetermined amount can be moved in the vertical direction of FIG.

  The crystal growth apparatus 60 is provided with a gas supply pipe 28 through which a raw material gas is injected while penetrating a lower flange 61 that closes the lower end of the reaction vessel 21 and entering a predetermined amount into the reaction vessel 21. The gas supply pipe 28 is disposed in a state where the injection port thereof is oriented in a direction substantially perpendicular to the crystal growth surface of the substrate 26. That is, the gas supply pipe 28 is in a state in which the injection port 28a is located directly below the center of the crystal growth surface of the substrate 26 and faces the crystal growth surface of the substrate 26 substantially vertically and faces upward. It is arranged by.

  In addition, the crystal growth apparatus 60 is provided with an auxiliary gas supply pipe 62 that penetrates the lower flange 61 with a predetermined distance from the gas supply pipe 28 and enters a predetermined amount into the reaction vessel 21. The gas supply pipe 62 is formed shorter than the length of the gas supply pipe 28 in the reaction vessel 21 by a predetermined length. From the auxiliary gas supply pipe 62, a gas that does not directly contribute to the reaction, such as nitrogen gas or hydrogen gas, is injected toward the outer peripheral portion of the substrate 26.

  Then, as described above, the substrate 26 is installed at an arbitrary position in the reaction vessel 21 by moving the susceptor rod 22 in the vertical direction, and the distance from the gas supply pipe 28 can be set. .

  When crystal growth is performed using the crystal growth apparatus 60, an eddy current is generated in the susceptor 24 by the induction heating coil 29, and the substrate 26 is heated using the susceptor 24 as a heating source. Source gases TMG, TMA, TMI, ammonia, hydrogen, and nitrogen are injected toward the substrate 26.

  Since the temperature of the gas injected from the gas supply pipe 28 is lower than the temperature in the vicinity of the substrate 26, the susceptor 24, or the susceptor holder 27, it is heated on the surface of the substrate 26 and heat convection is generated. However, the thermal convection of the source gas is performed in a state where the substrate 26 is disposed with its crystal growth surface facing downward, and the gas supply pipe 28 injects the source gas from below the substrate 26 toward the crystal growth surface. Since it is disposed, it flows outward in the radial direction from the center of the substrate 26, and a fresh raw material gas can always be supplied to the crystal growth surface of the substrate 26.

  Further, nitrogen gas and hydrogen gas that do not directly contribute to the reaction are injected from the auxiliary gas supply pipe 62 so as to surround the outside of the raw material gas injected from the gas supply pipe 28 toward the substrate 26, and the gas supply pipe 28. Therefore, it is possible to further suppress the spread of the source gas injected toward the crystal growth surface of the substrate 26 and further improve the supply efficiency of the source gas to the crystal growth surface of the substrate 26.

  Accordingly, a high-quality GaN-based semiconductor crystal film can be grown on the surface of the substrate 26 with a smaller amount of raw material gas with a simple structure and an inexpensive crystal growth apparatus 60.

  Further, a gas that does not directly contribute to the reaction injected from the auxiliary gas supply pipe 62 flows between the inner wall of the reaction vessel 21 and the raw material gas injected from the gas supply pipe 28, and is injected from the auxiliary gas supply pipe 62. As a result, the temperature rise near the inner wall of the reaction vessel 21 is suppressed by the gas, and the source gas is diluted near the inner wall of the reaction vessel 21 by the gas injected from the auxiliary gas supply pipe 62, and GaN to the inner wall of the reaction vessel 21 is reduced. Adhesion of the system material film can be reduced.

  Therefore, the film adhering to the inner wall of the reaction vessel 21 becomes thick, so that it is possible to prevent deterioration of crystallinity and yield due to film peeling, and to prevent this deterioration of crystallinity and yield. In addition, the number of times of washing the reaction vessel 21 can be reduced, and the utilization efficiency of the crystal growth apparatus 60 can be improved.

  Furthermore, the crystal growth apparatus 60 can control the spread of the source gas injected from the gas supply pipe 28 by adjusting the flow rate of the gas injected from the auxiliary gas supply pipe 62, and grow GaN on the substrate 26. It is possible to easily improve the uniformity of the film thickness and characteristics of the system crystal film.

  In the present embodiment, TMG, TMA, TMI, ammonia, hydrogen, and nitrogen are used as source gases. However, any source gas that can grow a GaN-based crystal can be used. The same applies to.

  In addition, the material of the components in the reaction vessel 21 of the crystal growth apparatus 60 is not limited to the above as long as it fulfills the function described above.

  Furthermore, as long as the auxiliary gas supply pipe 62 is located outside the gas supply pipe 28, the position and number thereof can be arbitrarily set.

  FIG. 8 is a diagram showing a seventh embodiment of the crystal growth apparatus and crystal growth method of the present invention, and FIG. 8 applies the seventh embodiment of the crystal growth apparatus and crystal growth method of the present invention. It is the front schematic block diagram seen from the surface substantially parallel with respect to the flow of the reaction gas of the crystal growth apparatus.

In the present embodiment, a gas that does not directly contribute to the reaction is disposed extending to the outer peripheral position of the substrate and the second gas supply pipe that injects a gas that does not directly contribute to the reaction toward the substrate. A gas introduction pipe to be introduced into the reaction vessel is provided and corresponds to claims 1 and 2 .

  The present embodiment is applied to a crystal growth apparatus similar to the crystal growth apparatus 60 of the sixth embodiment. In the description of the present embodiment, the crystal of the sixth embodiment is used. The same components as those of the growth apparatus 60 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 8, the crystal growth apparatus 70 holds the substrate 26 with the crystal growth surface facing downward by the holding part 27 a of the susceptor 24 and the susceptor holder 27, and the upper side of the susceptor 24 is below the susceptor rod 22. A susceptor cover 32 attached to the tip is disposed. On the upper side of the susceptor cover 23, a communication tube 25 having a hole through which the susceptor rod 22 is formed is disposed. In addition, a predetermined amount can be moved in the vertical direction of FIG.

  In the crystal growth apparatus 70, a gas supply pipe 28 is disposed so as to pass through a lower flange 61 that closes the lower end of the reaction vessel 21 and enter a predetermined amount into the reaction vessel 21. The injection port 28 a is disposed in a state of being substantially perpendicular to the crystal growth surface of the substrate 26. That is, the gas supply pipe 28 is in a state in which the injection port 28a is located directly below the center of the crystal growth surface of the substrate 26 and faces the crystal growth surface of the substrate 26 substantially vertically and faces upward. It is arranged by.

  Further, the crystal growth apparatus 70 is provided with an auxiliary gas supply pipe 62 that penetrates the lower flange 61 with a predetermined distance from the gas supply pipe 28 and enters a predetermined amount into the reaction vessel 21. The gas supply pipe 62 is formed shorter than the length of the gas supply pipe 28 in the reaction vessel 21 by a predetermined length. From the auxiliary gas supply pipe 62, a gas that does not directly contribute to the reaction, such as nitrogen gas or hydrogen gas, is injected toward the outer peripheral portion of the substrate 26.

  Further, the crystal growth apparatus 70 is provided with a gas introduction pipe 71 that penetrates the lower flange 61 in a state of surrounding the periphery of the gas supply pipe 28 and enters a predetermined amount into the reaction vessel 21. 71, the tip of the reaction vessel 21 is formed in a conical shape whose diameter is wider toward the tip, the tip extends to the substrate 26 side than the injection port 28a of the gas supply pipe 28, and The length is set slightly above the substrate 26 held by the susceptor 24. In other words, the crystal growth apparatus 70 is arranged in a state where the substrate 26 held by the susceptor 24 is located in the tip of the gas introduction pipe 71 that is open in a conical shape.

  Then, as described above, the substrate 26 is installed at an arbitrary position in the reaction vessel 21 by moving the susceptor rod 22 in the vertical direction, and the distance from the gas supply pipe 28 can be set. .

  When crystal growth is performed using this crystal growth apparatus 70, an eddy current is generated in the susceptor 24 by the induction heating coil 29, and the substrate 26 is heated using the susceptor 24 as a heating source. Source gases TMG, TMA, TMI, ammonia, hydrogen, and nitrogen are injected toward the substrate 26.

  Further, from the auxiliary gas supply pipe 62, nitrogen gas or hydrogen gas that does not directly contribute to the reaction is injected so as to surround the outside of the raw material gas injected from the gas supply pipe 28 toward the substrate 26, and the gas introduction pipe 71. , Nitrogen gas or hydrogen gas that does not directly contribute to the reaction is introduced into the reaction vessel 21.

  Since the temperature of the gas injected from the gas supply pipe 28 is lower than the temperature in the vicinity of the substrate 26, the susceptor 24, or the susceptor holder 27, it is heated on the surface of the substrate 26 and heat convection is generated. However, the thermal convection of the source gas is performed in a state where the substrate 26 is disposed with its crystal growth surface facing downward, and the gas supply pipe 28 injects the source gas from below the substrate 26 toward the crystal growth surface. Since it is disposed, it flows outward in the radial direction from the center of the substrate 26, and a fresh raw material gas can always be supplied to the crystal growth surface of the substrate 26.

  The gas that does not directly contribute to the reaction injected from the auxiliary gas supply pipe 62 and the gas introduction pipe 71 suppresses the spread of the source gas injected from the gas supply pipe 28 toward the crystal growth surface of the substrate 26, The supply efficiency of the source gas to the crystal growth surface of the substrate 26 can be further improved. In particular, the gas introduction pipe 71 is disposed between the inner wall of the reaction vessel 21 and the susceptor holder 27 so that the distal end thereof extends to a position surrounding the outer periphery of the substrate 26, and the gas introduction pipe 71 can be used with a smaller amount of gas. It is possible to further improve the supply efficiency of the source gas to the crystal growth surface of the substrate 26 by suppressing the spread of the source gas injected from the supply pipe 28 toward the crystal growth surface of the substrate 26.

  In the present embodiment, TMG, TMA, TMI, ammonia, hydrogen, and nitrogen are used as source gases. However, any source gas that can grow a GaN-based crystal can be used. The same applies to.

  In addition, the material of the components in the reaction vessel 21 of the crystal growth apparatus 70 is not limited to the above as long as it fulfills the function described above.

  Furthermore, as long as the auxiliary gas supply pipe 62 is located outside the gas supply pipe 28, the position and number thereof can be arbitrarily set.

  FIG. 9 is a perspective view of a semiconductor laser 80 to which the GaN-based semiconductor crystal film created by the crystal growth apparatus of each of the above embodiments is applied.

In FIG. 9, a semiconductor laser 80 has a GaN-based semiconductor film 82 sequentially formed on a sapphire crystal growth substrate 81. The GaN-based semiconductor film 82 includes an n-type GaN contact layer 83, an n-type Al layer from the lower layer. _x Ga _(1-x) N cladding layer 84, GaN / In _y Ga _(1-y) N multilayer quantum well active layer 85, p-side Al _x Ga _(1-x) N cladding layer 86, p-side GaN contact layer 87 are sequentially laminated. Here, x = 0.2 and y = 0.05.

  These stacked crystal layers are etched up to the n-type GaN contact layer 83 so that the n-type electrode 88 can be in contact with the n-type GaN contact layer 83, and the n-type electrode 88 and the n-type GaN contact layer 83 are etched. Are ohmic junctions. In the stacked crystal layer, the light emitting end face from which the laser light L is emitted and the end face opposite to the light emitting end face from which the laser light L is emitted are also etched in a direction substantially perpendicular to the ray direction of the laser light L. An end face is formed.

  The p-type electrode 89 is formed on the p-type GaN contact layer 87, which is the uppermost layer of the crystal layer. By applying a current to the p-type electrode 89 and the p-type electrode 89 by applying a cathode and an anode electrode, respectively, Laser light L is emitted from the light emitting end face.

  Such a semiconductor laser 80 can produce a high-quality semiconductor laser 80 with a simple structure and an inexpensive crystal growth apparatus by using the crystal growth apparatus and the crystal growth method of each of the above embodiments. Can do.

  Although the semiconductor laser 80 including the multilayer quantum well active layer has been described with reference to FIG. 9, a single-layer quantum well active layer, an SCH (Separate Confinement Heterostructure) structure, or a structure that performs laser oscillation such as a combination thereof is also described. The same can be applied. The present invention can also be applied to devices requiring high quality crystallinity such as light receiving elements such as photodiodes and electronic devices such as heterojunction transistors.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the scope of the invention. Needless to say.

BRIEF DESCRIPTION OF THE DRAWINGS It is a front schematic block diagram of the crystal growth apparatus to which 1st Embodiment of the crystal growth apparatus and crystal growth method of this invention is applied. It is a figure which shows the relationship between each crystal growth process by the crystal growth apparatus and crystal growth method to which 2nd Embodiment of the crystal growth apparatus and crystal growth method of this invention is applied, and temperature. It is a front schematic block diagram of the crystal growth apparatus to which 3rd Embodiment of the crystal growth apparatus and crystal growth method of this invention is applied. It is a perspective view of the susceptor holder used for the crystal growth apparatus to which 4th Embodiment of the crystal growth apparatus and crystal growth method of this invention is applied. It is a perspective view of the conventional susceptor holder. It is a front schematic block diagram of the crystal growth apparatus to which 5th Embodiment of the crystal growth apparatus and crystal growth method of this invention is applied. It is a front schematic block diagram of the crystal growth apparatus to which 6th Embodiment of the crystal growth apparatus and crystal growth method of this invention is applied. It is a front schematic block diagram of the crystal growth apparatus to which the 7th Embodiment of the crystal growth apparatus and crystal growth method of this invention is applied. 1 is a perspective view of a semiconductor laser 80 to which a GaN-based semiconductor crystal film created by a crystal growth apparatus and a crystal growth method of the present invention is applied. FIG. It is a front schematic block diagram of the crystal growth apparatus of the conventional MO-VPE method. The front schematic block diagram of the other conventional crystal growth apparatus.

Explanation of symbols

20 crystal growth apparatus 21 reaction vessel 22 susceptor rod 23 susceptor cover 24 susceptor 25 communication pipe 26 substrate 27 susceptor holder 27a holding part 28 gas supply pipe 28a injection port 29 induction heating coil 30 crystal growth apparatus 31 susceptor holder 31a holding part 32 susceptor Cover 40 susceptor holder 41 film 42 susceptor holder 43 film 50 crystal growth apparatus 60 crystal growth apparatus 61 lower flange 62 auxiliary gas supply pipe 70 crystal growth apparatus 71 gas introduction pipe 80 semiconductor laser 81 substrate 82 GaN-based semiconductor film 83 n-type GaN contact layer 84 n-type Al _x Ga _(1-x) N cladding layer 85 GaN / In _y Ga _(1-y) N multilayer quantum well active layer 86 p-side Al _x Ga _(1-x) N cladding layer 87 p-side GaN contact layer 88 n-type electrode 89p type electrode

Claims (2)

The substrate held by the susceptor at a predetermined reaction vessel by injecting heated situ Tsuhara material gas to the substrate at a predetermined temperature, the crystal manufacturing apparatus for growing a crystal by vapor phase reaction, injecting the raw material gas A first gas supply pipe, a second gas supply pipe for injecting a second gas that does not directly contribute to the reaction, a gas introduction pipe for introducing a third gas that does not directly contribute to the reaction into the reaction vessel, A surface of the substrate on which crystal growth is performed is placed in a direction facing a vector opposite to gravity, and the source gas blowout port of the first gas supply pipe The second gas supply pipe is disposed in a state of facing substantially perpendicular to the surface of the substrate on which crystal growth is performed, and the second gas supply pipe faces in a direction facing the surface of the substrate on which crystal growth is performed. And outside the outer periphery of the substrate Towards a position disposed in a state of injecting the second gas, the gas introduction pipe is disposed at a position radially outward of the first gas supply pipe about said first gas supply pipe And the gas blowout port extends from the direction facing the surface of the substrate on which crystal growth is performed to the substrate side from the blowout port of the first gas supply pipe. A crystal manufacturing apparatus, wherein the crystal manufacturing apparatus is disposed so as to extend to a radially outer position at substantially the same position as a surface on which growth is performed. The substrate held by the susceptor at a predetermined reaction vessel by injecting heated situ Tsuhara material gas to the substrate at a predetermined temperature, the crystal production method to grow a crystal by vapor phase reaction, injecting the raw material gas A first gas supply pipe that injects a second gas that does not directly contribute to the reaction, and a gas introduction pipe that introduces a third gas that does not directly contribute to the reaction into the reaction vessel. The surface on the side of the substrate on which crystal growth is performed is placed in a state facing the vector in the direction opposite to the direction of gravity, and the surface of the substrate on the side on which crystal growth is performed is approximately The source gas is blown out from the source gas blowing port of the first gas supply pipe disposed in a vertically opposed state to the surface of the substrate on which crystal growth is performed, and the substrate on which crystal growth of the substrate is performed From the direction almost opposite to the surface A second gas that does not directly contribute to the reaction is injected from the second gas supply pipe toward a position outside the outer periphery of the substrate, and the first gas supply pipe is centered on the first gas supply pipe. The gas blowout port is disposed at a radially outer position and extends to the substrate side from the blowout port of the first gas supply pipe from a direction facing the surface of the substrate on the crystal growth side. to a third gas which does not contribute directly to the reaction from extending to a position substantially radially outward of the same position as the side surface of crystal growth of the substrate is disposed said gas inlet tube A crystal manufacturing method characterized in that the crystal growth is performed by introducing.

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